Thanks. Ok, now i see the effects of changing the width.
While playing with different values I see some effects, which i can not explain at the moment.
First, what happens if the width I want to set is to small for the entries of the columns/cells?
Second, it seems that the width I want to set does not have the same (or even no) effect on the header/footer of the table.
I added a new copy of the table (.tablepress-id-6) at the top of blog post. Of course the settings (width 10px) is nearly senseless (for the most columns, not for all) but there you can see the difference I mean in header, rows and footer.